TYPHUS FEVER, an acute infectious disease, highly con tagious, lasting for about fourteen days, and characterized mainly by great prostration of strength, severe nervous symptoms, and a peculiar eruption on the skin. It has received numerous other names, such as pestilential, putrid, jail, hospital fever, exanthe matic typhus, etc. It appears to have been known for many centuries in epidemic form, in all countries in Europe. The best accounts of the disease are those given by old English writers, who narrate its ravages in towns and describe many "black assizes," in which it was communicated by prisoners brought into court to the judges, jurymen, court officials, etc., with fatal effect. Typhus fever has been observed in almost all parts of the world ; but it is most frequent in temperate or cold climates.
Of predisposing causes the most powerful are overcrowding and poverty. Armies in the field are also liable to suffer from this disease ; for instance, during the Crimean War it caused an enor mous mortality among the French troops. It is now known to be conveyed by lice (see ENTOMOLOGY, Medical).
Typhus is now regarded as certainly due to the action of a filter passing virus (q.v.) but the relation of this to certain minute bodies found in the spleen and known as Rickettsia bodies from their discoverer is not yet certain.
2. The invasion begins in general, with a rigor, headache and sleeplessness. The temperature rises to 103°-105° F, at which it continues with little daily variation until about the period of the crisis. The pulse is rapid (Ioo-12o or more) and at first full, but later feeble. The tongue, at first coated with a white fur, soon becomes brown and dry, while sordes (dried mucus, etc.) accumu late upon the teeth ; the appetite is gone ; and intense thirst pre vails. The bowels are as a rule constipated, and the urine is diminished in amount and highly coloured.
3. The third stage is characterized by the appearance of the
eruption, which generally shows itself about the fourth or fifth day or later, and consists of dark red (mulberry-coloured) spots or blotches varying in size from mere points to three or four lines in diameter, very slightly elevated above the skin, at first disap pearing on pressure, but tending to become both darker and more permanent. They appear chiefly on the abdomen, sides, back and limbs, and occasionally on the face. Besides this characteristic typhus rash, there is usually a general faint mottling all over the surface. The rash is rarely absent. In the more severe and fatal forms of the fever slight subcutaneous haemorrhages (petechiae) are to be seen in abundance. After the appearance of the eruption the patient's condition seems to be easier, so far as regards the headache and discomfort which marked the outset of the symp toms; but this is also to be ascribed to the tendency to pass into the typhous stupor which supervenes about this time, and becomes more marked throughout the course of the second week. Marked leucocytosis is present and is considered to be diagnostic in doubt ful cases when the rash is badly marked. The patient now lies on his back, with a dull dusky countenance, an apathetic or stupid expression, and contracted pupils. Delirium, usually of a low muttering kind, but sometimes wild and maniacal (delirium ferox), is present both by night and day. The peculiar condition to which the term "coma vigil" is applied, in which the patient, though quite unconscious, lies with eyes widely open, is regarded, espe cially if persisting for any time, as an unfavourable omen. Through the second week the symptoms continue unabated.
4. A crisis or favourable change occurs about the i4th day, and is marked by a more or less abrupt fall of the temperature and of the pulse, slight perspiration, discharge of loaded urine, re turn of moisture to the tongue, and a change in the patient's look, which shows signs of returning intelligence. Although the sense of weakness is extreme, convalescence is in general steady and comparatively rapid.